In the steel industry, a basic metal workpiece often called a slab, billet or bloom, is pushed or walked through a reheat furnace thereby heating the workpiece in order to make it more malleable during the subsequent reworking procedure. In a pusher type furnace, a complex infrastructure of water-cooled vertical and cross pipes supports a series of water-cooled skid pipes over which the workpieces are pushed. The skid pipes themselves are insulated except for a metal skid or bead atop the pipe which supports the workpiece.
Conventional skid pipes have been round pipes with a skid welded on top of the pipe. A newer, superior pipe design as described and claimed in U.S. Pat. No. 4,253,826 comprises a truncated triangular pipe which can have as the workpiece support a welded bead on top or simply no additional structure whatsoever.
A problem to be solved in the reheat furnace is the reduction of cold spots on the underside of the workpiece. These cold spots can be caused by the shadow effect of the pipe which shields part of the hot furnace gases from rigorous actions of the workpiece. Cold spots can also occur as a result of heat transfer from the workpiece into the internally cooled skid pipe itself. It is the latter problem to which the present invention applies.